In a computerized environment, data may be provided in a form of a graph. A graph is a set of nodes and edges. Each edge connects at least two nodes of the graph. The graph may be labeled, such as by providing a label for each node of the graph.
One note worthy sub-class of the graph data structure is a tree. A tree is a graph that does not contain any loops. One node in the tree is deemed as the root node from which the tree is seen as starting. Each node may have child nodes to which it is connected. A node having no child nodes is referred to as a terminal node or as a leaf. The tree is also characterized as not containing any loop.
Both trees and graphs contain structural information (also known as topology), indicating a relationship between different nodes. Data that is embodied in a graph or a tree may be expressed by the structure of the data structure itself.